Multi-functional telemetry device
Special design for stand along, remote LED and LCD displays
What is it's purpose?
Monitoring an environment data such as temperature and humidity near the display control PC, getting external temperature and measurement installation power consumption.
Story
On up on a time a company decided to control huge LCD displays, installed in Warsaw, Poland.
The reason -troubles with connection via internet and unpredictable freezes. Main idea of the device is acquiring environment data such as temperature and humidity near the display control PC, getting external temperature and measurement installation power consumption. All data sends to display control PC. Control PC right after the data has been received, should send the answer. If there are no answer, the device forces Control PC hardware restart.
The device emulated virtual COM port. Data is sending to PC as a text frame every 300ms.
Key futures
• Power monitoring (total and current power consumption),
• Central computer watch dog function,
• Getting a values from external light sensor, external temperature and humidity sensor, onboard temperature sensor.
• Designed the USB interface to PC and defined the handshake protocol for communicating to PC software, devised and implemented user tunable settings.
• 4 optically isolated inputs (for door switches and other external units)
• 8 power relay outputs (for Control PC, 4G LTE modem, etc.)
After prototype has been accepted, I created PCB project.
Within 10 days I got perfect quality target PCB boards from China. Next the control systems has been delivered to my client.
Project description
Hardware.
Hardware built on STM32F103C8 controller. Sensors: external temperature DS18B20, DHT22 humidity and temperature, ambilight GL5516 photo-resistor Power monitoring- SCT013 current transformer.
PCB
2 layers PCB created in KiCAD.
Firmware
Firmware is written in C
using PlatformIO
and some Arduino libraries.
How does it work?
The device emulated virtual COM port. Data is sending to PC as a text frames every 300ms:
